88 



University of California Publications. [Geology 



tiful lilac spodumene, kunzite. Beryl, topaz, and garnet of gem 

 quality are also mined in the county, but these possess less value 

 than the tourmaline and kunzite. 



A crystal of eolumbite and several of beryl from San Diego 

 County were loaned to the writer by Mr. Lazard Calm, and a 

 brief description is given here. 



Occurrence. — The crystal of columbite came from the Little 

 Three mine, near Ramona. It is short prismatic, measuring about 

 2 centimeters in length and width and is partly broken, so that 

 some of the faces have been destroyed. Notwithstanding its 

 broken condition, there are thirty-six faces present, representing 

 thirteen forms, one of which is new. 



Forms. — The observed forms are : 



a | 100 | z | 150} s \22l\ 



b j010( y J 160 1 n ) 211 1 



m j 110 1 e J 021 f P \V2l\ 



g jl30| u Jlllj o jl3l| 



r \ 141 1 new 



Measurements. — The crystal was measured with the two-circle 

 goniometer, and the average values for </j and p for the thirteen 

 forms are shown in the following table : 



No. 



Letter 



Symbol 

 Gdt. Miller 



4 



Measured 



P 





4 



Calculated 

 ' P 





1 



b 



Ooc 



010 



0° 



00' 



90° 



00' 



0° 



00' 



90° 



00' 



o 



a 



ocO 



100 



89 



45 



90 



00 



90 



00 



90 



00 



3 



nt 



cc 



110 



68 



46 



90 



00 



68 



05 



90 



00 



4 



9 



oc3 



130 



39 



31 



90 



00 



39 



38 



90 



00 



5 





oc5 



150 



25 



32 



90 



00 



26 



26 



90 



00 



6 



y 



cc 6 



160 



22 



26 



90 



00 



22 



30 



90 



00 



7 



h 



02 



021 







36 



35 



16 







00 



35 



36 



8 



r 



14 



141 



31 



28 



60 



09 



31 



52 



59 



19 



9 







13 



131 



39 



31 



54 



32 



39 



38 



54 



21 



10 



P 



12 



121 



51 



30 



49 



59 



51 



11 



48 



48 



11 



u 



1 



111 



67 



36 



43 



59 



68 



05 



43 



48 



12 



s 



9 



221 



68 



42 



62 



30 



68 



05 



62 



28 



13 



n 



21 



211 



78 



53 



61 



46 



78 



37 



61 



09 



The faces of n and s were dull and the rest bright but some- 

 what vicinal or wavy, so that close readings could not be had. 



The new form r (141) had narrow faces, but all four on the 

 upper half of the crystal were present. Fig. 1, PL 10, shows the 

 crystal as it appears. 



